Multi-stage gradient reinforced composite filler for high-filled embankment and construction process of multi-stage gradient reinforced composite filler

Abstract

The invention discloses a multi-stage gradient reinforced composite filler for a high-filling embankment and a construction process of the multi-stage gradient reinforced composite filler, and belongs to the technical field of embankment fillers, and in the multi-stage gradient reinforced composite filler, the overall structure stability is remarkably improved through layered material combination. The self-locking structure of the three-level aggregate enhances the non-deformability of the filler, the large-particle-size broken stones form skeleton support, the modified fly ash fills pores to improve the compactness, and the machine-made sand surface treatment technology enhances the cohesive force among particles. The cementitious material realizes synergistic development of early strength and later strength, rapid hardening of the sulphoaluminate cement and continuous hydration of the superfine slag powder cooperate with each other, and the microstructure is optimized in cooperation with the nano material. The gradient reinforcement system exerts characteristics of different materials in a layered mode, the deep steel-plastic belt anchors the foundation to prevent slippage, the middle-layer fiber grid disperses stress, the surface-layer non-woven fabric inhibits shallow-layer cracking, three-dimensional protection from inside to outside is formed, microcracks are continuously repaired through the microbial agent, shrinkage deformation is compensated through the expanding agent, and the long-term service performance is comprehensively guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of embankment filling technology, specifically a multi-stage gradient reinforced composite filler for high-fill embankments and its construction process. Background Technology

[0002] Multi-level gradient reinforced composite filler is an advanced engineering material. Its core feature lies in its precise design, achieving a multi-level structural gradient change from macroscopic to microscopic within the material, and incorporating reinforcing materials. This filler is typically composed of a matrix material and dispersed reinforcing materials (such as fibers, whiskers, or special particles). Its "gradient" characteristic means that the material's composition, structure, or properties (such as density, strength, and thermal conductivity) change continuously or gradually from one end to the other to adapt to complex stress distributions or specific functional requirements. The "reinforcement" significantly improves the overall mechanical properties of the filler, such as tensile, shear, and impact resistance, and enhances its stability and durability. This composite filler exhibits excellent performance in civil engineering, soil and rock reinforcement, and environmental remediation, effectively controlling settlement, enhancing structural stability, and can be customized according to specific application scenarios, representing an important development direction for modern high-performance filler technology.

[0003] However, traditional high-fill embankment construction technology often results in insufficient structural stability due to the single gradation of fill material. Ordinary crushed stone soil lacks effective interlocking between particles and is prone to uneven settlement. Conventional reinforcement methods often use the same type of material to lay flat, failing to match the stress characteristics according to the depth difference. Shallow reinforcement is prone to failure and deep anchorage is insufficient. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-stage gradient reinforced composite filler for high-fill embankments and its construction process in order to solve the problems mentioned above.

[0005] The technical solution adopted in this invention is as follows: a multi-stage gradient reinforced composite filler for high-fill embankments, the filler comprising;

[0006] I. Aggregate System:

[0007] 25 portions of Grade I basalt gravel;

[0008] 32 portions of secondary manufactured sand;

[0009] 19 portions of grade III modified fly ash;

[0010] II. Cementitious system: 12 parts of sulfoaluminate cement;

[0011] Four parts of nano-metakaolin;

[0012] 5 parts of slag powder;

[0013] III. Gradient Reinforcement System:

[0014] Deep reinforcement: 5 parts of steel-plastic composite strip;

[0015] Intermediate layer reinforcement: 3 layers of basalt fiber mesh;

[0016] Surface reinforcement: 2 parts of polyester fiber nonwoven fabric;

[0017] IV. Functional Modifier: 1.2 parts of organosilicon waterproofing agent;

[0018] Sodium pyrophosphate retarder 0.8 parts;

[0019] 1.5 parts of calcium oxide expanding agent;

[0020] 0.5 parts of compound microbial inoculant.

[0021] In a preferred embodiment, a construction process for multi-stage gradient reinforced composite fill material for high-fill embankments is characterized by the following steps:

[0022] S1: Clear the construction area and level the ground. Use a heavy roller to pre-compact the foundation to ensure that the bearing capacity of the base meets the design standards. Excavate transverse drainage blind ditches and lay permeable geotextiles to form continuous drainage channels.

[0023] S2: The manufactured sand and silane coupling agent are premixed in proportion to achieve a uniform coating state. Modified fly ash and calcium carbonate whiskers are processed by a high-speed vortex mixer to complete fiber dispersion modification. The steel-plastic composite belt is cut to the designed length and the ends are heat-sealed.

[0024] S3: A twin-shaft forced mixer is used to sequentially add basalt crushed stone, pretreated manufactured sand and modified fly ash for dry mixing. Sulfoaluminate cement, nano-meta-kaolin and slag powder are added and mixing continues. Finally, a mixture of organosilicon waterproofing agent, sodium pyrophosphate retarder, calcium oxide expansion agent and compound microbial agent is added to control the total moisture content within the standard range.

[0025] S4: The filling operation is carried out in three layers. The thickness of the deep filling layer is controlled to be 50cm after compaction, the middle layer 40cm, and the surface layer 30cm. Before each layer is paved, a total station is used for positioning and layout to ensure that the cross slope is consistent with the road crown design.

[0026] S5: Immediately after deep filling, steel-plastic composite strips are laid, arranged in parallel at 80cm longitudinal intervals and pre-tensioned. During the middle layer filling, basalt fiber mesh is embedded and anchored to the underlying soil using U-shaped nails. Before the surface layer is laid, polyester fiber non-woven fabric is covered, extending 1.5m beyond the shoulder and manually leveled.

[0027] S6: The deep layer is compacted 6 times with a 32-ton heavy vibratory roller; the middle layer is compacted 5 times with a 26-ton bump roller; and the surface layer is compacted 3 times with an 18-ton double-drum roller. The overlap width of the compaction tracks is maintained at one-third of the wheel width, and two additional passes are made at the edges for additional compaction.

[0028] S7: Immediately after compaction, cover with composite geomembrane for moisture retention and curing. During the curing period, spray mist water containing microbial nutrient solution three times a day (morning, noon, and evening). Curing time is 7 days for deep areas, 5 days for middle layers, and 3 days for surface layers. Mechanical traffic is prohibited during the curing period.

[0029] S8: The overall stiffness was tested using a falling weight deflectometer after every three layers of filling, and the compaction degree of each layer was measured using a nuclear density meter. The overlap length of the reinforcement material was checked using a laser rangefinder. The final slope was compared with the design model using a 3D laser scanner, and areas with deviations exceeding 3mm were milled and repaved.

[0030] In a preferred embodiment, in step S1, the base treatment stage requires three passes of pre-compaction on the original ground using a vibratory roller with a capacity of 18 tons or more, with the compaction speed controlled within 2.5 km / h per pass. Transverse drainage blind ditches are excavated according to a standard longitudinal spacing of 15m and a cross-sectional size of 30×40cm. The ditches are backfilled in layers with crushed stone of 10–30mm particle size and coated with 200g / m³ of material. 2 Long-filament geotextiles should be used, with a strict 20cm overlap between adjacent geotextiles. The compaction degree of the base layer, as tested by the sand cone method, must reach over 93%, and localized weak areas should be treated with lime-soil replacement.

[0031] In a preferred embodiment, in step S2, during the material pretreatment process, manufactured sand and KH-550 silane coupling agent are dry-mixed at a mass ratio of 0.5% in a 60°C oven for 20 minutes to complete surface modification. Modified fly ash and 15μm diameter calcium carbonate whiskers are added to a vortex mixer at a ratio of 9:1, and continuously stirred at a speed of 1800rpm for 8 minutes to achieve fiber dispersion. The steel-plastic composite belt is cut to the designed length plus a 30cm allowance, and the ends are sealed with a 380°C hot-melt welding gun to form an anti-spreading head structure.

[0032] In a preferred embodiment, in step S3, the mixing operation uses a JS2000 twin-shaft mixer. First, basalt crushed stone is added and dry-mixed for 45 seconds to ensure uniform aggregate distribution. Then, pretreated manufactured sand, modified fly ash, and cementitious materials are added sequentially and mixed continuously for 90 seconds. The liquid modifier is premixed according to the ratio of organosilicon waterproofing agent: retarder: expanding agent: bacterial agent = 12:8:15:5, and then injected uniformly through a metering pump in the last 30 seconds. The total mixing time is controlled to be 165±5 seconds, and the discharge moisture content is calibrated to 8.2% in real time using a microwave moisture meter.

[0033] In a preferred embodiment, during step S4, when constructing the layered filling, the deep layer uses a backward unloading method to spread a loosely laid mixture with a thickness of 65cm. After initial leveling with a bulldozer, an automatic grader with an elevation sensor is used for fine leveling. The middle layer uses a progressively laid 40cm loose layer, with longitudinal joints staggered by no less than 2m. The surface 30cm loose layer is constructed in two sections, each with a width exceeding the designed slope line by 50cm. The cross slope of each layer is dynamically monitored using a laser level, and an automatic leveling system is activated to correct the deviation when it exceeds 0.5%.

[0034] In a preferred embodiment, during step S5, the deep steel-plastic composite strip is laid with a longitudinal spacing of 80cm and a transverse length, and a 3% preload is applied using a 50kN hydraulic tensioner. Before laying the middle-layer basalt grid, it is activated by soaking in an alkaline solution with pH=10 for 2 hours, and the grid joints are anchored with galvanized U-shaped nails at 30cm intervals. The surface non-woven fabric is connected by double-row polypropylene thread, with a stitch width of 8cm and a stitch spacing of 5cm. The outer shoulder extension is secured with sandbags to prevent displacement.

[0035] In a preferred embodiment, in step S6, the vibration compaction process follows the principle of "static first, then vibration, from slow to fast." During the deep, high-frequency vibration stage, a 28Hz high-frequency vibration mode is activated, maintaining a wheel track overlap width of 40cm. The middle layer uses 25Hz medium-frequency vibration combined with 50cm staggered wheel compaction. During the final compaction of the surface layer, the vibration system is turned off, and a 1:3 oil-water mixture is sprayed onto the steel wheel surface to prevent sticking. The compaction degree of each layer is tested using both the sand cone method and the nuclear method, with a requirement of 97% for the deep layer, 96% for the middle layer, and 95% for the surface layer.

[0036] In a preferred embodiment, in step S7, the curing system is covered with a two-layer, one-membrane composite geotextile within 30 minutes after final compaction, and the seams are sealed with special tape to form a closed curing environment. The microbial nutrient solution is prepared at a ratio of glucose:calcium nitrate:potassium dihydrogen phosphate = 5:3:2, and sprayed daily at 09:00, 14:00, and 18:00 using a high-pressure mist cannon, with a single spray volume controlled at 0.8 L / m². 2 During the maintenance period, embedded temperature and humidity sensors are used to monitor and ensure that the internal humidity is ≥90% and the temperature is maintained at 20-35℃.

[0037] In a preferred embodiment, in step S8, the quality closed-loop control sets five inspection nodes: every three layers are filled, a 50kg drop weight deflectometer is used at test points at 20m intervals, and the rebound modulus must be >80MPa; the strength of the steel-plastic strip joint is verified by on-site shear test, and the shear strength is >85kN / m; the completed slope is generated into a point cloud model by three-dimensional laser scanning, and the height difference is compared with the BIM design model with an allowable deviation of ±5cm; during final acceptance, a φ150mm core sample is drilled for unconfined compressive strength test, and the 28-day strength should be ≥15MPa.

[0038] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0039] 1. In this invention, the overall structural stability is significantly improved through layered material combinations. The self-locking structure of the three-stage aggregate enhances the deformation resistance of the filler, large-diameter crushed stone forms a skeleton support, modified fly ash fills the pores to improve density, and the surface treatment technology of manufactured sand strengthens the interparticle bonding force. Cementitious materials achieve synergistic development of early strength and later strength, and the rapid hardening of sulfoaluminate cement and the continuous hydration of slag micro powder work together, with nanomaterials optimizing the microstructure. The gradient reinforcement system leverages the different material properties in layers: the deep steel-plastic strip anchors the foundation to prevent slippage, the middle layer of fiber mesh disperses stress, and the surface non-woven fabric inhibits shallow cracking, forming a three-dimensional protection from the inside out. Functional modifiers specifically improve environmental adaptability, waterproofing agents block rainwater penetration, microbial agents continuously repair micro-cracks, and expansion agents compensate for shrinkage deformation, comprehensively ensuring long-term service performance.

[0040] 2. In this invention, layered filling and compaction processes are matched with different material properties. Deep-layer strong vibration compaction ensures foundation density, mid-layer cam rolling enhances interlocking, and surface static pressure maintains a complete interface. Gradient reinforcement precise positioning technology ensures effective stress distribution of the reinforcement material, deep pre-tensioning eliminates installation stress, mid-layer anchoring maintains the grid pattern, and surface extension laying prevents slope collapse. Collaborative maintenance measures balance strength development and ecological protection. Composite geotextile moisture retention and microbial nutrient solution spraying create a stable maintenance environment, promoting cementitious material hydration and microbial activity. A full-process quality inspection system enables dynamic control, deflection testing controls overall stiffness, three-dimensional scanning ensures slope alignment, and core sample testing verifies final strength, forming a complete quality closed loop from construction to acceptance. Attached Figure Description

[0041] Figure 1 This is a schematic diagram illustrating the process principle of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0043] Example:

[0044] Reference Figure 1 A multi-stage gradient reinforced composite filler for high embankments, comprising:

[0045] I. Aggregate System:

[0046] 25 portions of Grade I basalt gravel;

[0047] 32 portions of secondary manufactured sand;

[0048] 19 portions of grade III modified fly ash;

[0049] II. Cementitious system: 12 parts of sulfoaluminate cement;

[0050] Four parts of nano-metakaolin;

[0051] 5 parts of slag powder;

[0052] III. Gradient Reinforcement System:

[0053] Deep reinforcement: 5 parts of steel-plastic composite strip;

[0054] Intermediate layer reinforcement: 3 layers of basalt fiber mesh;

[0055] Surface reinforcement: 2 parts of polyester fiber nonwoven fabric;

[0056] IV. Functional Modifier: 1.2 parts of organosilicon waterproofing agent;

[0057] Sodium pyrophosphate retarder 0.8 parts;

[0058] 1.5 parts of calcium oxide expanding agent;

[0059] 0.5 parts of compound microbial inoculant.

[0060] Includes the following steps:

[0061] S1: Clear the construction area and level the ground. Use a heavy roller to pre-compact the foundation to ensure that the bearing capacity of the base meets the design standards. Excavate transverse drainage blind ditches and lay permeable geotextiles to form continuous drainage channels.

[0062] S2: The manufactured sand and silane coupling agent are premixed in proportion to achieve a uniform coating state. Modified fly ash and calcium carbonate whiskers are processed by a high-speed vortex mixer to complete fiber dispersion modification. The steel-plastic composite belt is cut to the designed length and the ends are heat-sealed.

[0063] S3: A twin-shaft forced mixer is used to sequentially add basalt crushed stone, pretreated manufactured sand and modified fly ash for dry mixing. Sulfoaluminate cement, nano-meta-kaolin and slag powder are added and mixing continues. Finally, a mixture of organosilicon waterproofing agent, sodium pyrophosphate retarder, calcium oxide expansion agent and compound microbial agent is added to control the total moisture content within the standard range.

[0064] S4: The filling operation is carried out in three layers. The thickness of the deep filling layer is controlled to be 50cm after compaction, the middle layer 40cm, and the surface layer 30cm. Before each layer is paved, a total station is used for positioning and layout to ensure that the cross slope is consistent with the road crown design.

[0065] S5: Immediately after deep filling, steel-plastic composite strips are laid, arranged in parallel at 80cm longitudinal intervals and pre-tensioned. During the middle layer filling, basalt fiber mesh is embedded and anchored to the underlying soil using U-shaped nails. Before the surface layer is laid, polyester fiber non-woven fabric is covered, extending 1.5m beyond the shoulder and manually leveled.

[0066] S6: The deep layer is compacted 6 times with a 32-ton heavy vibratory roller; the middle layer is compacted 5 times with a 26-ton bump roller; and the surface layer is compacted 3 times with an 18-ton double-drum roller. The overlap width of the compaction tracks is maintained at one-third of the wheel width, and two additional passes are made at the edges for additional compaction.

[0067] S7: Immediately after compaction, cover with composite geomembrane for moisture retention and curing. During the curing period, spray mist water containing microbial nutrient solution three times a day (morning, noon, and evening). Curing time is 7 days for deep areas, 5 days for middle layers, and 3 days for surface layers. Mechanical traffic is prohibited during the curing period.

[0068] S8: The overall stiffness was tested using a falling weight deflectometer after every three layers of filling, and the compaction degree of each layer was measured using a nuclear density meter. The overlap length of the reinforcement material was checked using a laser rangefinder. The final slope was compared with the design model using a 3D laser scanner, and areas with deviations exceeding 3mm were milled and repaved.

[0069] In step S1, the foundation treatment stage requires three passes of pre-compaction on the original ground using a vibratory roller with a capacity of 18 tons or more, with the compaction speed controlled within 2.5 km / h per pass. Transverse drainage blind ditches are excavated according to a standard longitudinal spacing of 15m and a cross-sectional size of 30×40cm. The ditches are backfilled in layers with crushed stone of 10–30mm particle size and wrapped with 200g / m² geotextile, with a strict 20cm overlap between adjacent geotextile sections. The foundation compaction degree, tested using the sand cone method, must reach at least 93%, and localized weak areas are treated with lime-soil replacement.

[0070] In step S2, during the material pretreatment process, manufactured sand and KH-550 silane coupling agent are dry-mixed at a mass ratio of 0.5% in a 60℃ oven for 20 minutes to complete surface modification. Modified fly ash and 15μm diameter calcium carbonate whiskers are added to a vortex mixer at a ratio of 9:1, and continuously stirred at a speed of 1800rpm for 8 minutes to achieve fiber dispersion. The steel-plastic composite belt is cut to the designed length plus a 30cm allowance, and the ends are sealed with a 380℃ hot melt welding gun to form an anti-spreading head structure.

[0071] In step S3, the mixing operation uses a JS2000 twin-shaft mixer. First, basalt crushed stone is added and dry-mixed for 45 seconds to ensure uniform aggregate distribution. Then, pretreated manufactured sand, modified fly ash, and cementitious materials are added sequentially and mixed continuously for 90 seconds. The liquid modifier is premixed according to the ratio of organosilicon waterproofing agent: retarder: expansion agent: bacterial agent = 12:8:15:5, and then injected uniformly in the last 30 seconds through a metering pump. The total mixing time is controlled at 165±5 seconds, and the discharge moisture content is calibrated to 8.2% in real time using a microwave moisture meter.

[0072] In step S4, during the layered filling construction, the deep layer uses a retreating unloading method to spread a loosely laid 65cm thick mixture. After initial leveling with a bulldozer, an automatic grader with an elevation sensor is used for fine leveling. The middle layer uses a progressively laid 40cm loose layer, with longitudinal joints staggered by no less than 2m. The surface 30cm loose layer is constructed in two sections, each extending 50cm beyond the designed slope line. The cross slope of each layer is dynamically monitored using a laser level, and the automatic leveling system is activated to correct any deviation exceeding 0.5%.

[0073] In step S5, during the gradient reinforcement process, the deep steel-plastic composite strip is laid with a longitudinal spacing of 80cm and a transverse length, and a 3% preload is applied using a 50kN hydraulic tensioner. Before laying the middle-layer basalt grid, it is soaked in an alkaline solution with pH=10 for 2 hours for activation, and the grid joints are anchored with galvanized U-shaped nails at 30cm intervals. The surface non-woven fabric is connected with double-row polypropylene thread, with a stitch width of 8cm and a stitch spacing of 5cm. The outer shoulder extension is secured with sandbags to prevent displacement.

[0074] In step S6, the vibration compaction process follows the principle of "static before vibration, and slow to fast." During the deep, high-frequency vibration stage, a 28Hz high-frequency vibration mode is activated, maintaining a 40cm overlap width between wheel tracks. The middle layer uses 25Hz medium-frequency vibration combined with 50cm staggered wheel compaction. During the final compaction of the surface layer, the vibration system is turned off, and a 1:3 oil-water mixture is sprayed onto the steel wheel surface to prevent sticking. The compaction degree of each layer is tested using both the sand cone method and the nuclear method, with a requirement of 97% for the deep layer, 96% for the middle layer, and 95% for the surface layer.

[0075] In step S7, within 30 minutes after final compaction, the same curing system is covered with a two-layer, one-membrane composite geotextile, and the seams are sealed with special tape to form a closed curing environment. The microbial nutrient solution is prepared at a ratio of glucose:calcium nitrate:potassium dihydrogen phosphate = 5:3:2, and sprayed daily at 09:00, 14:00, and 18:00 using a high-pressure mist cannon, with a single spray volume controlled at 0.8 L / m². 2 During the maintenance period, embedded temperature and humidity sensors are used to monitor and ensure that the internal humidity is ≥90% and the temperature is maintained at 20-35℃.

[0076] In step S8, the quality closed-loop control sets five inspection nodes: every three layers of filling are tested at 20m intervals using a 50kg drop weight deflectometer, and the rebound modulus must be >80MPa; the strength of the steel-plastic strip joint is verified by on-site shear test, and the shear strength is >85kN / m; the completed slope is generated into a point cloud model by 3D laser scanning, and the height difference is compared with the BIM design model with an allowable deviation of ±5cm; during the final acceptance, a φ150mm core sample is drilled for an unconfined compressive strength test, and the 28-day strength should be ≥15MPa.

[0077] Comparative example:

[0078] Comparative tests were conducted on two high embankment sections (embankment height 18-22 meters, slope gradient 1:1.5) with similar geological conditions selected from highway reconstruction and expansion projects:

[0079] Control group: Traditional graded crushed stone soil (60% crushed stone, 20% sand, and 20% clay) was used, and a single layer of biaxial tensile geogrid (tensile strength 50kN / m) was laid in the middle of the fill layer. During construction, a 22-ton road roller was used to compact the soil 6 times. During the curing period, watering was the only method of keeping the soil moist.

[0080] The data comparison is shown in the table below:

[0081]

[0082] As can be seen from the above, the overall structural stability of this invention is significantly improved through the layered material combination. The self-locking structure of the three-stage aggregate enhances the deformation resistance of the filler, large-diameter crushed stone forms a skeleton support, modified fly ash fills the pores to improve density, and the surface treatment technology of manufactured sand strengthens the interparticle bonding force. The cementitious material achieves synergistic development of early strength and later strength, the rapid hardening of sulfoaluminate cement and the continuous hydration of slag powder work together, and the nanomaterials optimize the microstructure. The gradient reinforcement system leverages the different material properties in layers: the deep steel-plastic strip anchors the foundation to prevent slippage, the middle layer of fiber mesh disperses stress, and the surface non-woven fabric inhibits shallow cracking, forming a three-dimensional protection from the inside out. Functional modifiers specifically improve environmental adaptability, waterproofing agents block rainwater penetration, microbial agents continuously repair micro-cracks, and expansion agents compensate for shrinkage deformation, comprehensively ensuring long-term service performance.

[0083] In this invention, layered filling and compaction processes are matched with different material properties. Deep-layer strong vibration compaction ensures a dense foundation, mid-layer cam rolling enhances interlocking, and surface static pressure maintains an intact interface. Gradient reinforcement precision positioning technology ensures effective stress distribution on the reinforcement materials, deep pre-tensioning eliminates installation stress, mid-layer anchoring maintains the grid pattern, and surface extension laying prevents slope collapse. Collaborative maintenance measures balance strength development and ecological protection; composite geotextile moisture retention and microbial nutrient solution spraying create a stable maintenance environment, promoting cementitious material hydration and microbial activity. A comprehensive quality monitoring system enables dynamic control; deflection testing controls overall stiffness, three-dimensional scanning ensures slope alignment, and core sample testing verifies final strength, forming a complete quality closed loop from construction to acceptance.

[0084] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0085] The foregoing description enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-stage gradient reinforced composite filler for high-fill embankments, characterized in that: The packing material includes; I. Aggregate System: 25 portions of Grade I basalt gravel; 32 portions of secondary manufactured sand; 19 portions of grade III modified fly ash; II. Cementitious system: 12 parts of sulfoaluminate cement; Four parts of nano-metakaolin; 5 parts of slag powder; III. Gradient Reinforcement System: Deep reinforcement: 5 parts of steel-plastic composite strip; Intermediate layer reinforcement: 3 layers of basalt fiber mesh; Surface reinforcement: 2 parts of polyester fiber nonwoven fabric; IV. Functional Modifier: 1.2 parts of organosilicon waterproofing agent; Sodium pyrophosphate retarder 0.8 parts; 1.5 parts of calcium oxide expanding agent; 0.5 parts of compound microbial inoculant.

2. The construction process of a multi-stage gradient reinforced composite fill for high embankments as described in claim 1, characterized in that: Includes the following steps: S1: Clear the construction area and level the ground. Use a heavy roller to pre-compact the foundation to ensure that the bearing capacity of the foundation meets the design standards. Excavate transverse drainage blind ditches and lay permeable geotextiles to form a continuous drainage channel. S2: The manufactured sand and silane coupling agent are premixed in proportion to achieve a uniform coating state. The modified fly ash and calcium carbonate whiskers are processed by a high-speed vortex mixer to complete fiber dispersion modification. The steel-plastic composite belt is cut to the designed length and the ends are heat-sealed. S3: A twin-shaft forced mixer is used to sequentially add basalt crushed stone, pretreated manufactured sand and modified fly ash for dry mixing. Sulfoaluminate cement, nano metakaolin and slag powder are added and mixing is continued. Finally, a mixture of organosilicon waterproofing agent, sodium pyrophosphate retarder, calcium oxide expansion agent and composite microbial agent is added to control the total moisture content within the standard range. S4: The filling operation is carried out in three layers. The thickness of the deep filling layer is controlled to be 50cm after compaction, the middle layer to be 40cm, and the surface layer to be 30cm. Before each layer is paved, a total station is used for positioning and layout to ensure that the cross slope is consistent with the road crown design. S5: After deep filling, steel-plastic composite strips are laid immediately, laid in parallel at a longitudinal spacing of 80cm and pre-tensioned; basalt fiber mesh is embedded during the middle filling and anchored to the lower soil using U-shaped nails; before the surface layer is laid, polyester fiber non-woven fabric is covered, with the fabric extending 1.5m to the outside of the shoulder and leveled manually. S6: The deep layer is compacted 6 times with a 32-ton heavy vibratory roller, the middle layer is compacted 5 times with a 26-ton bump roller, and the surface layer is compacted 3 times with an 18-ton double drum roller. The overlap width of the compaction track is maintained at one-third of the wheel width, and two additional compaction passes are added at the edges. S7: Immediately after compaction, cover with composite geomembrane for moisture retention and curing. During the curing period, spray mist water containing microbial nutrient solution three times a day, morning, noon and evening. Curing time is 7 days for deep areas, 5 days for middle areas and 3 days for surface areas. Mechanical passage is prohibited during the curing period. S8: The overall stiffness is tested by a falling weight deflectometer after every 3 layers of filling, and the compaction degree of each layer is measured by a nuclear density meter. The overlap length of the reinforcement material is checked with a laser rangefinder. Finally, the slope is compared with the design model using a 3D laser scanner. Areas with deviations exceeding 3mm are milled and repaved.

3. The construction process of a multi-stage gradient reinforced composite fill for high embankments as described in claim 1, characterized in that: In step S1, the base treatment stage requires the use of a vibratory roller with a capacity of 18 tons or more to perform three pre-compaction operations on the original ground, with the single-pass compaction speed controlled within 2.5 km / h; the transverse drainage blind ditch is excavated according to the standard of 15m longitudinal spacing and 30×40cm cross-section, and the ditch is backfilled in layers with crushed stone with a particle size of 10-30mm and wrapped with 200g / m³. 2 Long-filament geotextiles should be used, with the overlap width of adjacent geotextiles strictly maintained at 20cm; the compaction degree of the base layer should reach more than 93% as tested by the sand filling method, and local weak areas should be treated with lime-soil replacement.

4. The construction process of a multi-stage gradient reinforced composite fill for high embankments as described in claim 1, characterized in that: In step S2, during the material pretreatment process, manufactured sand and KH-550 silane coupling agent are dry-mixed in a 60°C oven at a mass ratio of 0.5% for 20 minutes to complete surface modification; modified fly ash and 15μm diameter calcium carbonate whiskers are added to a vortex mixer at a ratio of 9:1, and the mixture is continuously stirred at a speed of 1800rpm for 8 minutes to achieve fiber dispersion; the steel-plastic composite belt is cut to the designed length plus a 30cm allowance, and the ends are sealed with a 380°C hot melt welding gun to form an anti-spreading head structure.

5. The construction process of a multi-stage gradient reinforced composite fill for high embankments as described in claim 1, characterized in that: In step S3, the mixing operation uses a JS2000 twin-shaft mixer. First, basalt crushed stone is added and dry-mixed for 45 seconds to ensure uniform aggregate distribution. Then, pretreated manufactured sand, modified fly ash, and cementitious materials are added sequentially and mixed for 90 seconds. The liquid modifier is premixed according to the ratio of organosilicon waterproofing agent: retarder: expansion agent: bacterial agent = 12:8:15:5, and then injected at a uniform speed in the last 30 seconds through a metering pump. The total mixing time is controlled to be 165±5 seconds, and the discharge moisture content is calibrated to 8.2% in real time using a microwave moisture meter.

6. The construction process of a multi-stage gradient reinforced composite fill for high embankments as described in claim 1, characterized in that: In step S4, during the layered filling construction, the deep layer uses a backward unloading method to spread a loosely laid mixture with a thickness of 65cm. After the bulldozer initially levels it, an automatic grader with an elevation sensor is used for fine leveling. The middle layer uses a progressively laid 40cm loose layer with longitudinal joints staggered by no less than 2m. The surface 30cm loose layer is constructed in two sections, with each section extending 50cm beyond the designed slope line. The cross slope of each layer is dynamically monitored using a laser level, and the automatic leveling system is activated to correct the deviation when it exceeds 0.5%.

7. The construction process of a multi-stage gradient reinforced composite fill for high embankments as described in claim 1, characterized in that: In step S5, during the gradient reinforcement process, the deep steel-plastic composite strip is laid with a longitudinal spacing of 80cm and a transverse length, and a 3% pre-tightening force is applied using a 50kN hydraulic tensioner; the middle basalt grid is soaked in an alkaline solution with pH=10 for 2 hours before laying, and the grid joints are anchored with galvanized U-shaped nails at 30cm intervals; the surface non-woven fabric is connected by double-row sewing with polypropylene thread, with a sewing width of 8cm and a stitch spacing of 5cm, and the outer extension of the road shoulder is fixed with sandbags to prevent displacement.

8. The construction process of a multi-stage gradient reinforced composite fill for high embankments as described in claim 1, characterized in that: In step S6, the vibration compaction process follows the principle of "static first, then vibration, from slow to fast". In the deep layer strong vibration stage, a 28Hz high-frequency vibration mode is turned on, and the wheel track overlap width is maintained at 40cm. In the middle layer, a 25Hz medium-frequency vibration is used in conjunction with 50cm staggered wheel rolling. When the surface layer is finally compacted, the vibration system is turned off, and a 1:3 oil-water mixture is sprayed on the surface of the steel wheel to prevent it from sticking. The compaction degree of each layer is tested by both the sand cone method and the nuclear method, with the deep layer required to reach 97%, the middle layer 96%, and the surface layer 95%.

9. The construction process of a multi-stage gradient reinforced composite fill for high embankments as described in claim 1, characterized in that: In step S7, the curing system is covered with a two-layer geotextile and one-membrane composite geotextile within 30 minutes after final compaction, and the seams are sealed with special tape to form a closed curing environment; the microbial nutrient solution is prepared at a ratio of glucose:calcium nitrate:potassium dihydrogen phosphate = 5:3:2, and sprayed daily at 09:00, 14:00, and 18:00 using a high-pressure mist cannon, with a single spray volume controlled at 0.8L / m³. 2 During the maintenance period, embedded temperature and humidity sensors are used to monitor and ensure that the internal humidity is ≥90% and the temperature is maintained at 20-35℃.

10. The construction process of a multi-stage gradient reinforced composite fill for high embankments as described in claim 1, characterized in that: In step S8, the quality closed-loop control sets five inspection nodes: every three layers are filled, a 50kg drop weight deflectometer is used at test points at 20m intervals, and the rebound modulus must be >80MPa; the strength of the steel-plastic strip joint is verified by on-site shear test, and the shear strength is >85kN / m; the completed slope is generated into a point cloud model by three-dimensional laser scanning, and the height difference is compared with the BIM design model with an allowable deviation of ±5cm; during the final acceptance, a φ150mm core sample is drilled for an unconfined compressive strength test, and the 28-day strength should be ≥15MPa.

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